Abstract
	Knowledge of the relaxation properties of metal materials at high temperatures is necessary for the verification of susceptibility of castings to the creation of defects during the production process. Temperature limits of materials where highest tension values are generated may be detected with tensile tests under high temperatures. The generated tensions in the casting are a cause of the creation and development of defects.
	At acoustic emission (hereinafter called the "AE") use, tensile tests at high temperatures may, among other things, be used for analysis of the AE signal sources and set, in more detail, the temperature limit of elastic-plastic deformations existence in the material under examination. The AE is, during tensile tests at high temperatures, based on scanning of released elastic waves generated by sharp tension changes in the body as a result of the subsequent physical-metallurgical processes such as plastic deformation, tension redistributing, creation of microcracks and their spreading in macroscopic scale. 
	The results of the temperature drop where tension at casting cooling is generated or its release at heating are basic data for controlled cooling mode (and temperature of casting knocking out of the form) as well as necessary for the thermal mode for the casting tension reduction.
	The aim of the acoustic emission monitoring at tensile tests at higher temperatures is therefore the specification of the critical heat barrier of the elastic-plastic condition of materials and provision of information concerning the dynamics of deformation processes at tension including influences of surface layers for which acoustic emission, as confirmed by measurement results, a very suitable method.